<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>box-sizing属性</title>
		<style>
			#d1,#d2{
				height: 400px;
				width: 500px;
				border: 1px solid red;
			}
			#d2{
				padding: 20px;
				border-width: 40px;
				box-sizing: border-box;
			}
		</style>
	</head>
	<body>
		<div id="d1">111</div>
		<div id="d2">222</div>
	</body>
</html>